1. Field of the Invention
The present invention relates to a security system using an optical fiber barrier for detecting an invader breaking into an area surrounded by the barrier.
2. Prior Art
Conventionally, as a security system, employed are an infrared camera, a system using infrared rays, or a method of transmitting an optical signal through an optical fiber.
An area which can be watched by one unit of such an infrared camera, a system using infrared rays, or the like, has a limit, resulting in difficulty to watch a wide area. On the other hand, a conventional system using an optical fiber is used to detect whether the optical fiber is cut or not by a person. However, in these systems, repair has usually been required to recover the system, and a large amount of optical fiber is required so that the person cannot invade an area surrounded by the optical fiber without cutting the optical fiber.